In a powerful speech oscillating between anger and hope, artist Ben Quilty has blasted the Australians "devoid of compassion" who riddled Myuran Sukumaran with threats and criticism in his final months.

"We talked about [it], Australian people, mostly men, taking the time to address violent, threatening letters to my friend, all the way across the ocean in Indonesia," said Mr Quilty, who became Sukumaran's art mentor.

Both Sukumaran and Chan, who converted to Christianity and became an ordained pastor, were widely praised for changing their ways, starting prison programs, and helping fellow inmates also reform, during their 10 years at Kerobokan prison.

Mr Quilty, standing beside five of Sukumaran's haunting paintings, said it was hard to digest the posts and tweets on social media critical of the two men who worked to help others.

"Many Australians - I have to be honest - mostly men, completely devoid of any compassion. But if they had spent one hour with Myuran Sukumaran, I challenge any of them to continue their self-righteous and cruel tirade, for Myuran paved a way that contradicts the simplistic persona that they portray," he said.

He also hit back at media commentators who labelled him a "hypocrite" for supporting Sukumaran.

​In January, ​media personality Derryn Hinch said celebrities involved in the campaign to support the pair on death row were hypocritical for only opposing the death penalty when it was used against Australians.

"He said I should be working on all death penalty cases, and not just one. But Myuran was my friend and I wasn't going to let Myuran walk onto a green field in the dark and face a firing squad, while people like that radio announcer couldn't even name Myuran's name correctly," he said.

It is not alright to belittle young men when they are in hopeless and desperate situations

Mr Quilty also reprimanded the media for "mocking young men", pointing to a newspaper headline that read 'No Sympathy'. He said the day his friends and he lost their sympathy, was the day he would become "dead inside".

He said the public should accept the reality that young men often made "terrible, self-indulgent, dangerous" mistakes, at times, in an "awkward, rudderless, coming-of-age ritual". But in accepting this reality, the community should strive to understand boys and men better, providing guidance, mentoring, and inspiration.

Myruan Sukumaran's coffin arrives at the church ahead of his funeral. Photo: James Brickwood

"Men in my own society are riding a storm of violence right now. Women are not safe to walk the streets at night, women are not safe in their own homes," he said.

"Violence is not okay, it's not alright to use threats and bullyings to get your own way, to shirtfront, to name call. It is not alright to belittle young men when they are in hopeless and desperate situations, even if those young men got themselves into that place."

Sukumaran and Chan were caught attempting to smuggle 8.3 kilograms of heroin valued at $4 million in 2005. They were the leaders of the Bali nine drug smuggling ring. They were killed on April 29.

Mr Quilty also slammed the Australian government, saying: "I have profound questions about our government calling for the death penalty for citizens of other countries. It is not alright for us to call for the death penalty for anyone, anywhere, ever."

Balloons are released at the end of Myuran Sukumaran's funeral. Photo: James Brickwood

Mr Quilty shared how both men turned their lives around and transformed the prison community. Sukumaran's art classes were the first gatherings in the history of the prison where men and women could interact.

When Quilty gave $500 cash to Sukumaran for a painting, he was astonished that his friend gave it all away to the art students who needed it more than him.

A painting of Indonesian President Joko Widodo by Myuran Sukumaran. Photo: Zul Edoardo

At the end of the speech, Mr Quilty described Sukumaran's final artworks as the most powerful, anti-death penalty images the world had seen in a long time.

"Those paintings were not only images of salvation. Knowing Myuran, they were images to steer the world from the revolting barbarism that has overwhelmed Indonesian politics, and back to compassion," he said.